I want to automate the Excel process of Data → Import Text File → text import wizard
How do I find the PowerShell name for these menus?
Here i
Menu item names are there for the convenience of the user; labels you see there may or may not correspond directly to the COM methods you need to call. From any kind of a program (including a PowerShell script), you need to be interacting with the object model that the application exposes. Microsoft has Excel's documented at http://msdn.microsoft.com/en-us/library/wss56bz7.aspx
That said, depending on how many files you're working with and what exactly you need to do with them, going this route may be very slow and tedious. In many cases, it may be faster to treat Excel as an ODBC data source and insert your data into spreadsheets as though they were databases.